Cleveland Clinic: Weight-loss surgery can reverse diabetes

Gastric bypass surgery is superior to sleeve gastrectomy, medical therapy

Bariatric surgery may free many obese patients with type 2 diabetes from daily insulin and medication used to control their blood sugar levels, according to a new study published in NEJM

Cleveland Clinic researchers presented the results of the Stampede trial at the American College of Cardiology's (ACC) annual meeting this week in Washington, D.C. The study is one of the largest randomized controlled trials to examine the long-term efficacy of surgery for type 2 diabetes, which affects 23 million adults in the United States.

NEJM: Bariatric surgery may prevent diabetes

Details of the study

The researchers enrolled 150 overweight individuals with poorly controlled type 2 diabetes. They compared two types of weight-loss surgery to weight loss attained by diet, exercise, and nutritional counseling. The two surgeries were gastric bypass surgery, which involves rerouting the gastric pouch directly into the small intestine, and sleeve gastrectomy, where surgeons remove a portion of the stomach.

After three years, the study found that:

  • On average, gastric bypass and sleeve gastrectomy patients lost 24% and 21% of their body weight, respectively, about five or six times more weight than the medical therapy group;
  • 37.5% of gastric bypass patients and 24.5% of sleeve gastrectomy patients reduced their blood sugar below targets set by the American Diabetes Association, compared with 5% of patients in the medical therapy group; and
  • Only 5% to 10% of surgery patients who had been using insulin still needed the treatment, compared with 55% of patients in the medical therapy group.

The three-year data "confirm that bariatric surgery maintains its superiority over medical therapy for the treatment of type 2 diabetes in severely obese patients," says lead author Philip Schauer, director of the Bariatric and Metabolic Institute at the Cleveland Clinic. Even Type 2 patients who were mildly obese saw benefits from bariatric surgery, he noted.

NEJM debunks seven 'myths' about obesity

Overall, Schauer says that when compared to sleeve gastrectomy and medical therapy, gastric bypass patients "achieved greater weight loss, were on fewer medications, had a higher success rate in controlling their diabetes, and an improved quality of life." Additionally, bypass patients had improved kidney function—a benefit that was not detected in the other two groups.

A long-lasting effect

"Initially we thought diabetes was a disease you could not reverse or end. We do realize now that there may be a treatment that could end diabetes for some people and that's exciting," Sangeeta Kashyap, an endocrinologist at the Clinic, told Reuters. She added, "The fact that the surgeries can reverse the path of physiology of the disease is pretty remarkable."

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Balancing Medical and Surgical Weight Loss

Experts theorize that several factors may be at work in bypass patients that work against diabetes, such as increased insulin production after meals, changes in microbes, or hormones in the gut. "It's something about altered food delivery. It's not as simple as calories," says Robert Siegel, co-chair of the ACC meeting, who was not involved in the research.

Siegel believes the findings shed light on new treatment targets for diabetes drug development. "This opens up a whole new field of investigation and a lot of potential hope," he says, adding, "This is a totally different way of thinking about diabetes" (Berkrot/Pierson, Reuters, 3/31; Paddock, Medical News Today, 4/1; Shute, "Shots," NPR, 3/31).

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